1. Field of the Invention
The invention relates to a circuit and method of manufacture, and more particularly, to electromagnetic on chip shielding of a circuit (e.g. plurality of devices) and/or one or more devices formed on a semiconductor substrate, and a method of shielding devices and/or a circuit.
2. Background Description
In an attempt to solve RF interference problems, shielding structures in the metal level of a substrate have been utilized, but typically without a high doping layer in the substrate. Such structures also typically do not protect the devices in the substrate. They also lack feed through connection interface devices without degrading the shielding effectiveness such as feed through capacitors for the supply of power connections and DC signal connections, and/or transmission lines for the AC signal connections.
In high frequency, wide bandwidth and high gain applications, radiation shielding is becoming more and more necessary. This is particularly true in, e.g., cellular systems, which are very popular and which have to cope with lots of radiation signals in the air. Such signals can enter a cellular transceiver chip as unwanted signals and disturb the cellular phone operation. The path of an unwanted signal can enter the system either by direct radiation and/or by a metal connection, such as power connections. Furthermore, current system level shielding is expensive and incomplete due to many holes, e.g., holes for display and operation buttons, which exist in the shielding. In millimeter wave applications, the wavelength is approaching the connection length inside of a die and the radiation interference in a chip is getting stronger and stronger.
The protection of circuits sensitive to magnetic fields has also been utilized. One such method uses passivation of silicon dioxide or silicon nitride, i.e., isolated materials. However, these materials cannot be used to shield RF interference. Another method provides for dispersing of a shielding material powder. However, this is not usable as a high doping layer in a substrate.
The shielding of modules (package level) is also known. However, this shielding is not typically used in chip shielding and does not utilize feed through capacitors and/or transmission lines.
It is also known to construct an electromagnetic interference shield in a package assembling process. However, such shielding is not utilized for on-chip shielding and does not utilize transmission lines and/or feed through capacitors to minimize the possible leakage through connection openings.
A seal ring has been used to surround an LSI circuit to prevent dicing and bonding crack, and to improve moisture resistance. Such arrangements can use metal wiring and doping in silicon for the seal ring. However, such arrangements are not typically utilized for electromagnetic shielding. Furthermore, they typically lack a bottom conductive layer and a top wiring layer, and do not form a full box.
Packaging EMI has also been utilized, but not for chip shielding. Such packaging also does not utilize feed through capacitors or transmission lines, and does not form a complete shielding structure.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.